Study On Stability Of Filling Goaf Based On Arch Effect

For the mines that are mined by the filling method,the stability of filling gobs is an important condition for resource recovery and safe mining.If the fill-to-top ratio of the gob area is low,the empty areas will collapse in large areas,affecting the safety of mine production,and causing surface subsidence.The destruction of the ecological environment has become a serious engineering geological disaster.Therefore,the study of the stability of the filling gob area is of great significance to the safe production of the mine.The paper takes the mine which uses filling method as the research background.Based on the arch effect and structural mechanics theory,the related research is carried out through theoretical analysis,numerical simulation and on-site monitoring.The main work of the paper is as follows:(1)Based on the analysis of the failure modes of the goafs,the factors affecting the stability of the goafs are studied,including the structural factors of the goafs and external factors.And the manifestations of the arch effect are summarized,including the backfill arch effect,soil arch effect and rock arch effect.(2)Analysing the regularities of distribution of horizontal stress and vertical stress in the filling body under the influence of the arch effect,constructing the elastic beam mechanical model of the rib pillar and sill pillar under the effect of filling body,studying the influence of the arch effect on the stability of rib pillar,sill pillar and filling body.(3)Based on the study of the influence of the arch effect on the stability of rib pillar and sill pillar,using the elasticity theory and the ultimate strength criterion of the rock mass,the safety dimensions of rib pillar and sill pillar are calculated and analyzed,which provides pillar selection criteria for mine exploitation design.(4)Based on the caving characteristics of mine roof and the constraining effect of filling body in the goaf,the arch mechanical model of the roof is constructed,and the arch axial force analysis of the goaf under different roof-contacted filling rates is carried out,then the expressions of arch axial force in the worst section is deduced.According to the critical axial force discriminant,the stability of the roof in the goaf after filling is studied.The minimum roof-contacted filling rate for maintaining the goaf self-stabilization is proposed,which has a certain guiding effect on the mine filling project.